A Multidisciplinary Approach to the Management of Atypical Osseous Epithelioid Hemangioendothelioma

Hemangioendothelioma is a rare vascular tumor of intermediate malignant potential. Though epithelioid hemangioendothelioma (EH) is commonly found in soft tissues, it has been known to be present in skeletal tissues. The authors present a case of a 50-year-old woman diagnosed with EH of the iliac bone and acetabulum, who experienced pathological fracture at presentation. This report describes a multidisciplinary approach to the management that includes initial incisional biopsy, curettage, and bone grafting, followed by Intensity Modulated Radiation Therapy. The patient finally underwent hemipelvic resection with allograft reconstruction after recurrence. Histopathological study revealed osseous EH of low mitotic activity that stained positively for CD31, CD34, vimentin, and Factor VIII. Herein, the authors discuss the imaging characteristics, histopathological aspects, cytogenetic findings, and the radiobiological behavior of osseous EH. After an aggressive multidisciplinary intervention, the patient is able to achieve local control with no evidence of distal metastatic disease. 1. Introduction Hemangioendothelioma is a rare tumor that exhibits intermediate malignant potential, clinically behaving between benign hemangioma and malignant angiosarcoma. Epithelioid hemangioendothelioma (EH) is the most common histologic subtype that arises from vascular tissue [1] and represents less than one percent of all vascular neoplasms [2]. EH is most commonly found in soft tissues but can also be found in skeletal tissues such as skull, spine, pelvis, femur, and tibia [2]. Primary bone EH accounts for less than one percent of all malignant bone tumors [3]. For certain isolated tumors, curative resection with negative margins can achieve cure and long term local control. Role of chemotherapy and adjuvant radiation therapy remains unclear. Here, we report and discuss the management of epithelioid hemangioendothelioma of the acetabulum and the ilium in the setting of multidisciplinary approach, including orthopedic surgery, radiation oncology, medical oncology, interventional radiology, and pathology. 2. Case Report 2.1. Clinical History 50-year-old African American woman initially presented to the emergency department with a two-week history of vague right hip and lower pelvic pain. Her past medical history was significant for rheumatoid arthritis, diabetes mellitus type 1, and hyperthyroidism status after radioactive iodine ablation. No history of trauma or systemic etiology was found. Physical exam was unremarkable for motor or sensory neurological deficits. No